History

Symptoms of metabolic acidosis are not specific. The respiratory center in the brainstem is stimulated, and hyperventilation develops in an effort to compensate for the acidosis. As a result, patients may report varying degrees of dyspnea. Patients may also report chest pain, palpitations, headache, confusion, generalized weakness, and bone pain. Patients, especially children, also may present with nausea, vomiting, and decreased appetite.

The clinical history in metabolic acidosis is helpful in establishing the etiology when symptoms relate to the underlying disorder. The age of onset and a family history of acidosis may point to inherited disorders, which usually start during childhood. Important points in the history include the following:

Diarrhea - GI losses of HCO3-

History of diabetes mellitus, alcoholism, or prolonged starvation - Accumulation of ketoacids

Physical Examination

The best recognized sign of metabolic acidosis is Kussmaul respirations, a form of hyperventilation that serves to increase minute ventilatory volume. This is characterized by an increase in tidal volume rather than respiratory rate and is appreciated as deliberate, slow, deep breathing.

Chronic metabolic acidosis in children may be associated with stunted growth and rickets.

Coma and hypotension have been reported with acute severe metabolic acidosis.

Other physical signs of metabolic acidosis are not specific and depend on the underlying cause. Some examples include xerosis, scratch marks on the skin, pallor, drowsiness, fetor, asterixis, and pericardial rub for renal failure, as well as reduced skin turgor, dry mucous membranes, and fruity smell for DKA.

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: American Society of Nephrology<br/>Received income in an amount equal to or greater than $250 from: Healthcare Quality Strategies, Inc<br/>Received grant/research funds from Dept of Veterans Affairs for research; Received salary from American Society of Nephrology for asn council position; Received salary from University of Louisville for employment; Received salary from University of Louisville Physicians for employment; Received contract payment from American Physician Institute for Advanced Professional Studies, LLC for independent contractor; Received contract payment from Healthcare Quality Strategies, Inc for independent cont.

James W Lohr, MD Professor, Department of Internal Medicine, Division of Nephrology, Fellowship Program Director, University of Buffalo State University of New York School of Medicine and Biomedical Sciences